From: james@...
Date: 2002-03-28T01:44:06+09:00
Subject: RE: Hash.new(Hash.new) doesn't use Hash.new as default value

>
> Hi,
>
> In message "Re: Hash.new(Hash.new) doesn't use Hash.new as default value"
>     on 02/03/27, ts <decoux@moulon.inra.fr> writes:
>
> | With 1.7 you'll have the possibility to write
> |
> | Hash.new { Hash.new }
> |
> | and each times a key is not defined, ruby will evaluate the block, the
> | result of the block will be stored in the Hash and ruby will
> do what you
> | want.
>
> It does not store the evaluated default value.  Should it?

Do you mean something like


#----------------- 8< ------------------
h = Hash.new { |key| "There is no entry for '#{key.to_s}'" }

h["here"] = "OK"
puts h["missing"] # prints "There is no entry for 'missing'"

h.each{ |k,v| puts "#{k} => #{v} }
# prints
#   "here => OK"
#   "missing => There is no entry for 'missing'"
#----------------- 8< ------------------

Might be nice to allow returning one computed default value, but storing a
different computed default value.

James


>
> 							matz.
>